TSA said it also uncovered anomalies in some reports, such as missing data or calculation errors unrelated to safety, and as an extra precaution has ordered retesting for all full-body scanners as well as other x-ray equipment used to screen baggage that had inaccurate reports.

Some travelers and airline crews have expressed concerns about being repeatedly exposed to radiation from the body scanners, which TSA has deployed to thwart plots such as a passenger hiding a bomb under his or her clothes.

“Independent third-party testing has confirmed that all TSA technology is safe,” TSA Administrator John Pistole said in a statement. “TSA takes significant steps to ensure the safety and health of passengers and our workforce as we work to protect our nation from terrorist threats.”

TSA has accelerated deploying full-body scanners and other machines to detect explosives after a Nigerian man tried but failed to detonate a bomb hidden in his underwear on a flight from Amsterdam as it approached Detroit on Christmas Day 2009.

The full-body scanners provoked a backlash among some travelers who were upset because they produced a revealing picture of themselves without clothes as well as the potential for increased radiation exposure.

TSA has said repeatedly the radiation emitted is minimal and not dangerous, citing experts from the Food and Drug Administration and other third-party scientists. The agency is also testing new software to address privacy concerns.

There are about 486 full-body scanners in 78 airports around the U.S., of which 247 are so-called backscatter machines made by Rapiscan Systems, a unit of OSI Systems Inc., and expose a person to about 0.0025 millirem of radiation. The machines cannot produce more than 0.005 millirem per scan, according to TSA.

In comparison, a chest x-ray will expose someone to 10 millirem of radiation, and the maximum recommended exposure to radiation from man-made sources is 100 millirem per year, according to TSA.

To address the problems with the test reports, TSA said it would boost oversight of the testing and procedures. It also ordered contractors to retrain personnel conducting the surveys and requested the National Institute for Occupational Safety and Health to re-evaluate the TSA’s safety program.

“The mistakes were the result of calculating and procedural errors that were identified by Rapiscan management and have been corrected,” said Peter Kant, executive vice president of Rapiscan Systems.

He said the machines have fail-safe triggers to “shut down long before safety limitations could be reached.” Rapiscan said it has already rechecked about 105 of its machines and found no problems.

The radiation test reports, conducted at least once a year on the machines, will be posted to the TSA website, www.tsa.gov.